Pain is a sensory experience that may be described as the unpleasant awareness of a noxious stimulus or bodily harm. According to the International Association for the Study of Pain (IASP), pain is defined as an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage. Industry analysts estimate that more than 1.5 billion people around the world suffer from chronic pain, making it the number one reason patients seek medical care. Muscle pain in the shoulder-neck area or the upper or lower back is a very common problem.
Pain is a personal, subjective, multi-faceted construct under the influence of cultural learning and having physiological as well as (emotional and non-emotional) psychological elements. It is therefore inherently difficult if not impossible to assess in a truly objective manner because, on the one hand, two patients with identical physiological symptoms may experience their pain completely different due to differences in their sensitivity to pain or habituation to pain from earlier experiences.
Many techniques for pain treatment exist such as medication and physical exercises. Other solutions use heat and light therapy (e.g. Infra Red lamps). Increased temperature will stimulate thermal receptors in deep tissue. The thermal signal that the body generates then inhibits transmission of nociceptive signals. In addition, it causes physiological responses such as increased blood flow and metabolism, and is reported to relax muscles by decreasing the alpha motor activity from the dorsal horn.
An example of a phototherapy device is developed by Philips and has the form of an electronic patch designed to strip around the user's body for muscular backache. The patch has an array of blue Light Emitting Diodes (LEDs) in its inner part which can be switched on so as to deliver phototherapeutic blue light to an area of the skin of the user's body. A user can fasten the patch around his/her body using an elastic band, and thus the user can walk around with the patch kept in place, while receiving phototherapy.